Nepal earthquake a reminder of Big One that will strike California, says Dr. Lucy Jones

Saturday’s devastating earthquake in Nepal that has killed more than 3,200 people is the same magnitude temblor Los Angeles city officials and area residents need to be ready for, seismologist Lucy Jones said Sunday.

“This is their equivalent of what we talk about with the Shakeout Earthquake — a model of the Shakeout earthquake is (magnitude) 7.8,” said Jones, a Caltech-based science adviser for risk reduction at the U.S. Geological Survey. “It’s a very long fault that runs through a lot of inhabited regions. It’s what we should be preparing for.”

The Great California Shakeout is an annual drill that takes place each October to help people prepare and recover from a big earthquake. In Southern California, a 7.8-magnitude quake emanating along the southernmost segment of the San Andreas Fault — starting at the Salton Sea and heading toward Los Angeles — could result in more than 1,800 deaths, more than 50,000 injuries, $200 billion in damage and other losses and major disruptions to services, according to the Shakeout’s Website.

The last earthquake of that magnitude in California was the Great 1906 San Francisco Earthquake, which killed some 3,000 people and caused widespread destruction in the San Francisco Bay, Jones said. San Francisco has fault lines running under the city, just like Kathmandu — the capital of Nepal — does, she said.

“What matters is where the fault is,” Jones said. “In (Nepal’s) case, it’s underneath Kathmandu and it’s definitely the most inhabited part of Nepal. It’s over 100 kilometers long.”

The Nepal quake is also a reminder that a “really big earthquake” is sociologically very different from a smaller one, Jones said. The 6.7-magnitude Northridge earthquake in 1994, which left more than 55 people dead, involved only a 10-mile fault, though one that was located under a densely inhabited part of the city, Jones said.

“Imagine now, instead of 10 miles, we have 200 miles and you can see how much more damage there would be,” Jones said. “But there’s also a social disruption. When Northridge happened, most people were OK and could help those who weren’t. When you have an earthquake that’s much bigger and everyone is really affected, it’s much more difficult because you have no one to turn to.”

The Nepal earthquake was “very much anticipated” since major earthquakes occur along the Himalayan range and it’s an active plate boundary like the San Andreas Fault, said Susan Hough, also a Caltech-based USGS seismologist.

“Experts have talked for a long time about a potential repeat of a (magnitude) 8.1 earthquake in 1934, and other ‘gaps’ that will some day be filled by big earthquakes,” she said via email, noting this earthquake struck to the west of the 1934 break.

Early indications suggest that the shaking and damage in Kathmandu were not as severe as one might expect given that the fault moved at such shallow depths, she said. Well-built structures appear to have withstood the earthquake “quite well,” she said.

“There has been quite a bit of work done by local and international agencies to raise awareness and improve preparedness,” Hough said. “It appears to have made a difference, scarce resources notwithstanding.”

With the help of Jones, Los Angeles has started implementing changes to help the city better withstand and recover from such a major event. In the coming months, the City Council will examine resolutions on issues such as mandatory retrofit of soft-story apartments, which are those buildings that have parking or commercial space on the first floor and housing on higher floors, and upgrading building standards for free standing cell towers, she said.